Table 3.
Univariable Cox Proportional Hazards Analysis for Association of Baseline Clinical and High-Resolution Computed Tomography Variables with Disease Progression
| Predictor | HR (95% CI) | Standardized HR (95% CI) | P Value | C Statistic (95% CI) |
|---|---|---|---|---|
| Visual HRCT features | ||||
| Ground glass | 0.90 (0.31–2.63) | 0.97 (0.73–1.30) | 0.84 | 0.501 (0.423–0.578) |
| Ground glass reticular | 2.21 (1.44–3.39) | 1.57 (1.23–2.00) | 0.0003 | 0.671 (0.590–0.753) |
| Honeycombing | 1.11 (0.60–2.06) | 1.04 (0.82–1.33) | 0.74 | 0.516 (0.435–0.597) |
| Emphysema | 0.74 (0.17–3.21) | 0.94 (0.70–1.27) | 0.69 | 0.522 (0.459–0.584) |
| Normal | 0.78 (0.63–0.97) | 0.76 (0.60–0.96) | 0.02 | 0.610 (0.528–0.693) |
| AMFM HRCT features | ||||
| Ground glass | 1.09 (0.87–1.37) | 1.11 (0.85–1.44) | 0.45 | 0.532 (0.449–0.615) |
| Ground glass reticular | 1.37 (1.07–1.75) | 1.34 (1.07–1.68) | 0.01 | 0.647 (0.564–0.730) |
| Honeycombing | 1.02 (0.82–1.26) | 1.02 (0.79–1.33) | 0.87 | 0.506 (0.423–0.588) |
| Emphysema | 0.93 (0.25–3.38) | 0.99 (0.71–1.36) | 0.91 | 0.544 (0.461–0.627) |
| Normal | 0.87 (0.75–1.00) | 0.78 (0.61–1.00) | 0.054 | 0.611 (0.528–0.694) |
| Clinical variables | ||||
| Age, yr | 1.43 (1.01–2.03) | 1.35 (1.01–1.80) | 0.046 | 0.576 (0.494–0.659) |
| Male sex | 0.97 (0.52–1.80) | — | 0.92 | 0.504 (0.440–0.569) |
| Former smoker | 0.82 (0.46–1.48) | — | 0.51 | 0.538 (0.470–0.606) |
| FVC % predicted | 0.73 (0.58–0.88) | 0.59 (0.43–0.82) | 0.001 | 0.638 (0.555–0.721) |
| DlCO % predicted | 0.72 (0.55–0.94) | 0.67 (0.48–0.92) | 0.02 | 0.608 (0.525–0.691) |
| GAP stage | ||||
| 1 | Ref. | — | Ref. | 0.639 (0.565–0.714) |
| 2 | 1.68 (0.86–3.28) | — | 0.13 | — |
| 3 | 5.42 (2.53–11.63) | — | <0.0001 | — |
Definition of abbreviations: AMFM = adaptive multiple features method; CI = confidence interval; DlCO = diffusing capacity of the lung for carbon monoxide; GAP = gender-age-physiology; HR = hazard ratio; HRCT = high-resolution computed tomography.
Analysis includes n = 156 patients with both AMFM and visual scores for baseline HRCT and data on all included variables. Of 159 patients with baseline AMFM-scored HRCT, n = 1 subject was missing smoking status and n = 2 subjects were missing DlCO. Baseline characteristics for this subgroup, including number of events/outcomes, are shown in Table 1, column titled “Baseline HRCT.” Unstandardized HR is for each 10% increase in baseline total lung volume occupied by HRCT features and for each 10% increase in baseline % predicted FVC or DlCO, and for 10-year increase in age. Standardized HR is for each standard deviation increase in the continuous predictors. The categorical variables were not standardized. The GAP stage (24) is a mortality prediction model, incorporating age, sex, FVC, and DlCO, with higher GAP stages experiencing the worst outcomes. The outcome of interest is a composite FVC drop >10%, hospitalization, or mortality event.